DIETARY REGULATION OF SILENT SYNAPSES IN THE DORSOLATERAL STRIATUM.

Obesity results in circuit adaptations that closely resemble those induced by drugs of abuse. AMPA-lacking 'silent' synapses are critical in circuit generation during early development, but largely disappear by adulthood. Drugs of abuse increase silent synapses during adulthood and may facilitate the reorganization of brain circuits around drug-related experience, facilitating addiction and relapse Whether obesity causes addiction-related synaptic circuit reorganization via alterations in silent synapse expression has not been examined. Using a dietary-induced obesity paradigm, we show that mice that chronically consumed high-fat diet (HFD) exhibit upregulated silent synapses in both direct and indirect pathway medium spiny neurons in the dorsolateral striatum. Both the onset of silent synapses and their re-silencing after HFD withdrawal occur on an extended time scale of weeks rather than days. Our data suggest that HFD-related silent synapses likely arise from AMPA receptor internalization rather than through de novo synaptogenesis of NR2B-containing NMDA receptors. These data demonstrate that chronic consumption of high-fat diet can alter mechanisms of circuit plasticity, likely facilitating neural reorganization analogous to that observed with drugs of abuse.

A Targeted Gene Panel That Covers Coding, Non-coding and Short Tandem Repeat Regions Improves the Diagnosis of Patients With Neurodegenerative Diseases.

Genetic testing for neurodegenerative diseases (NDs) is highly challenging because of genetic heterogeneity and overlapping manifestations. Targeted-gene panels (TGPs), coupled with next-generation sequencing (NGS), can facilitate the profiling of a large repertoire of ND-related genes. Due to the technical limitations inherent in NGS and TGPs, short tandem repeat (STR) variations are often ignored. However, STR expansions are known to cause such NDs as Huntington's disease and spinocerebellar ataxias type 3 (SCA3). Here, we studied the clinical utility of a custom-made TGP that targets 199 NDs and 311 ND-associated genes on 118 undiagnosed patients. At least one known or likely pathogenic variation was found in 54 patients; 27 patients demonstrated clinical profiles that matched the variants; and 16 patients whose original diagnosis were refined. A high concordance of variant calling were observed when comparing the results from TGP and whole-exome sequencing of four patients. Our in-house STR detection algorithm has reached a specificity of 0.88 and a sensitivity of 0.82 in our SCA3 cohort. This study also uncovered a trove of novel and recurrent variants that may enrich the repertoire of ND-related genetic markers. We propose that a combined comprehensive TGPs-bioinformatics pipeline can improve the clinical diagnosis of NDs.

Sapien 3 Transcatheter Aortic Valve Implantation With Moderate or Without Predilation.

OBJECTIVES: Aortic valve preparation with balloon aortic valvuloplasty (BAV) has been previously considered mandatory during transcatheter aortic valve implantation (TAVI) procedures. BAV-inherent risks including stroke, conduction abnormalities, and reduced device profile size established the rationale for safe valve deployment without the need for aggressive valve preparation. We investigate the feasibility and safety of performing Sapien 3 (S3; Edwards Lifesciences) balloon-expandable TAVI with moderate or without predilation (PD). METHODS: We examined consecutive patients with severe aortic stenosis who underwent S3-TAVI at our institution. Overall, 119 patients underwent TAVI without PD and 126 with moderate PD (mean valvuloplasty balloon diameter, 15.3 ± 2.1 mm). TAVI endpoints and adverse events were considered according to the Valve Academic Research Consortium (VARC)-2 definitions. RESULTS: Device success for the entire cohort was 98.8%. PD rates were similar between groups. Total fluoroscopy time and amount of contrast used were lower in the no PD group (13 min vs 16.2 min [P<.001] and 71.3 mL vs 81 mL [P=.03], respectively). All-cause mortality up to 30 days was 0% (0/119) in the no PD group vs 1.6% (2/126) in the moderate PD group (P=.49). VARC-2 defined complication rates at 30 days including cerebrovascular accident were similar between groups. Overall, there was no significant difference in survival rate between both groups (hazard ratio, 3.6; 95% confidence interval, 0.80-16.2; P=.09). CONCLUSIONS: Balloon-expandable TAVI using the S3 device with moderate or without balloon PD is feasible and safe. Omission of PD in appropriate cases was associated with reduced fluoroscopy time and total contrast used without affecting procedural success.

Meta-analysis of the age-related positivity effect: age differences in preferences for positive over negative information.

In contrast to long-held axioms of old age as a time of "doom and gloom," mounting evidence indicates an age-related positivity effect in attention and memory. However, several studies report inconsistent findings that raise critical questions about the effect's reliability, robustness, and potential moderators. To address these questions, we conducted a systematic meta-analysis of 100 empirical studies of the positivity effect (N = 7,129). Results indicate that the positivity effect is reliable and moderated by theoretically implicated methodological and sample characteristics. The positivity effect is larger in studies that do not constrain (vs. constrain) cognitive processing-reflecting older adults' natural information processing preferences-and in studies incorporating wider (vs. narrower) age comparisons. Analyses indicated that older adults show a significant information processing bias toward positive versus negative information, whereas younger adults show the opposite pattern. We discuss implications of these findings for theoretical perspectives on emotion-cognition interactions across the adult life span and suggest future research directions.

Aggressive immunosuppression minimization reduces graft loss following diagnosis of BK virus-associated nephropathy: a comparison of two reduction strategies.

BACKGROUND AND OBJECTIVES: BK virus-associated nephropathy (BKVAN) has emerged as a leading cause of kidney graft loss, with no known predictors for graft loss and no consensus regarding treatment other than reduction of immunosuppression. DESIGN, SETTING, PARTICIPANTS AND MEASUREMENTS: A single-center retrospective analysis was performed of all cases of BKVAN from 1999 to 2005 for clinical predictors of graft loss, with evaluation of the impact of immunosuppression withdrawal (3-drug to 2-drug immunosuppression) within the first month versus reduction of immunosuppression. RESULTS: Of 910 kidney transplants, 35 (3.8%) cases of BKVAN were diagnosed at a median of 15 months after transplant (range, 5.5 to 90 months after transplant), 16 (46%) of which progressed to graft failure at a median of 11 months (range, 2 to 36 months) after diagnosis. Depleting antibody induction was a significant risk factor for graft loss on univariate analysis, whereas early drug withdrawal (<1 mo following diagnosis) protected against graft loss. On multivariate analysis, these findings were independent predictors of graft outcomes. Additionally, when patients were comanaged by referring nephrologists and the transplant center before the diagnosis of BKVAN, the risk of graft loss was 11-fold higher (P = 0.03) than if patients were managed solely by the transplant center. CONCLUSIONS: Increased awareness and early diagnosis of BKVAN, with aggressive tapering of immunosuppression once established, is critical to preserve kidney graft function. Early drug withdrawal to low-dose two-drug therapy maintenance may be preferable to a general reduction of agents.

Detection of donor-specific antibodies using HLA-coated microspheres: another tool for kidney transplant risk stratification.

BACKGROUND: Sensitive techniques are able to detect low levels of circulating antibodies. For many newer techniques, the clinical consequences of these antibodies are unknown. We hoped to determine the significance of antibodies detected through the use of Luminex microsphere-based assay. METHODS: Patients who received kidney transplants between March 2003 and May 2004 with negative anti-human globulin-augmented complement-dependent cytotoxicity (AHG-CDC) crossmatches were retested for pre-transplant panel reactive antibodies (PRA) using Luminex microspheres and stored sera. Patients were considered to have circulating antibodies if either class I or class II Luminex PRA was >or=15%. These patients were then analysed for pre-transplant donor-specific antibodies (DSA). Clinical outcomes were compared in patients with and without DSAs. RESULTS: Out of 136 patients who underwent transplantation, 55 had Luminex PRA >or=15%. Of these 55 patients, only 16 had a standard PRA >or=30% and 75% had a history of a sensitizing event. Twenty out of 55 patients were DSA+. Patients with DSA detected by Luminex had higher rates of primary non-function (PNF), delayed graft function, biopsy-proven acute rejection, and lower rates of graft survival at 6 months. A combined endpoint of immunological and clinical events was far more common in patients with DSA. CONCLUSION: The detection of DSAs by Luminex microspheres was associated with significantly higher rates of graft dysfunction and immunological events. Conversely, the presence of antibodies but no DSA by Luminex was associated with excellent outcomes. In patients with negative AHG-CDC crossmatches, the occurrence of low-level DSA by Luminex could assist in identifying patients that require more aggressive immune monitoring or immunosuppressive strategies.